The ability to provide long-distance wireless communication in dangerous and/or obstructed environments, for example in underground mines, is essential for both efficient operation and safety. In some applications, such as coal mining, communications systems are required by regulations for post-accident communications. In these mining operations, transmitting communication signals through earth, water and rock, for example, in addition to the large amounts of steel and concrete used in associated structures, severely impact the effective range of a communications signal. This is especially true with systems transmitting radio frequency signals through, for example, conventional electric dipole antennas.
Magnetic communications systems (MCSs) that provide low-frequency magnetic signals offer an increased ability to transmit through these materials. For example, a MCS may be used to provide emergency communication between a site deep within an underground mine and a second distant site, either on the surface or also within the mine. These systems typically operate with relatively weak signals and severe interference as a result of above-described interferences, both natural and manmade. This interference limits the ability of the MCS receiver to detect and demodulate the underlying signal, limiting the system's effective range as a result. Improved methods to eliminate or reduce these interferences are therefore desired.